Pregnancy of unknown location or PUL

This leaflet is to help you understand what Pregnancy of Unknown Location (PUL) is, what are its symptoms, what tests do you need, and what should you be watching out for?

What is a PUL?

You have had an ultrasound scan to check that your pregnancy is developing normally.  Unfortunately, we were unable to see the pregnancy on the screen today.  This is an inconclusive scan.  There are 3 possible reasons for this:

1. A very small normal pregnancy in the uterus (womb). The pregnancy may be normal, but too small to be seen on scan.  This usually happens in women who are unsure of their dates or have long menstrual cycles.
2. A miscarriage. The pregnancy may have already been lost and passed out with bleeding and therefore cannot be seen on scan.  In these cases, the pregnancy test may remain positive for many weeks after the miscarriage.
3. An ectopic pregnancy. The pregnancy may be developing outside the uterus. The most common site for an ectopic pregnancy to grow is in the fallopian tubes and this may be difficult to see on scan. An ectopic pregnancy can be a serious condition because it may cause internal bleeding, so we need to monitor women in this situation very carefully. 

What are the symptoms of a PUL?

A PUL can give no symptoms at all or you may experience abdominal pain or some vaginal bleeding. The presence of these symptoms don’t help in determining the location of the pregnancy. In the case of severe pain or very heavy vaginal bleeding, however, you should seek medical care immediately.

Should I have more tests done?

Your doctor will counsel you about the best option for follow-up. This usually involves measuring levels of pregnancy hormones in your blood, usually ‘hCG’ (which stands for ‘human chorionic gonadotrophin’ and is what gives you a positive result on a urine pregnancy test) and sometimes a hormone called progesterone. Some women will also have to come back for a second hCG level to be taken 48 hours later. Depending on the results, your doctor will tell you what the most likely outcome of your pregnancy is and what the next best steps are. We will continue to monitor you until we can confirm the outcome of your pregnancy, which may take up to two weeks. We will discuss each result with you in detail and try to keep you as informed as possible during this time.

What are the things to watch for?

Women with a PUL can have an ectopic pregnancy and this can be potentially dangerous if the pregnancy ‘ruptures’ and causes severe internal bleeding. It is therefore important that if you experience severe pain or any other worrying symptoms that you attend your nearest emergency department immediately. Thankfully, most women with a PUL, even those with an ectopic pregnancy, do not experience this.

Last updated October 2019